I. Field
The present invention relates generally to communication, and more specifically to techniques for scheduling measurements for neighbor cells in multiple wireless communication systems.
II. Background
In a Global System for Mobile Communications (GSM) system, a terminal communicates with one base station at any given moment but periodically makes measurements for neighbor base stations. The base station that the terminal communicates with is referred to as the “serving” cell, and the neighbor base stations are referred to as “neighbor” cells. The measurements are made so that the terminal can determine if there are any cells better than the current serving cell. This may be the case, for example, if the terminal is mobile and moves from cell to cell. If a better cell is found, as indicated by the measurements, then the terminal would be handed from the current serving cell over to the better cell, which would then become the new serving cell.
GSM provides gaps in the transmissions on the downlink and uplink to facilitate measurement for neighbor cells. These gaps have a predetermined duration and are spaced apart by a predetermined time interval. The terminal uses the gaps to make measurements for the neighbor cells and then reports the measurement results back to the serving cell.
A multi-mode terminal is capable of communicating with multiple wireless communication systems, such as a GSM system and a Wideband Code Division Multiple Access (W-CDMA) system. If the multi-mode terminal is in communication with the GSM system, then the terminal would make measurements for GSM neighbor cells and may also need to make measurements for W-CDMA neighbor cells. The gaps in transmission in the GSM system are originally intended for use to make measurements for GSM cells. Thus, using these gaps for other purposes, such as to make measurements for W-CDMA cells, may degrade the performance of the measurements for GSM cells.
There is therefore a need in the art for techniques to schedule measurements for neighbor cells in multiple wireless communication systems.